oldravendale
Western Thunderer
At Christmas I was lucky enough to receive a voucher for the Engineering Tour of Tower Bridge. For anybody with an interest in Victorian engineering this has to be one of the visits of the year. I went last Saturday. The tour was scheduled to take two hours. Three and a quarter hours later I was leaving the complex.
I'm publishing this on WT because, although peripheral, it does involve some amazing engineering.
Here's a selection of the one hundred plus photos I took.
First of all one has to do the tourist bit. That includes walking across both the high level walkways with views up and down the river but also through the new glass floor.
Then in to one of the towers where the architecture has been exposed and some effort made to show the internal complexities of the building.
Then the engineering tour proper for which the guide was a real bridge engineer - not the greatest presenter but a man who knows the bridge inside out. This is the old control room, no longer in use but retained. It's similarity to a signal box is very marked. These levers operated not only the lifting of the bascules but the withdrawing of the bolts which hold the bridge at the joint. There is a cam which lifts the bridge off the bearings for road traffic and the lift itself requires several lever movements as different levels of stored power are brought in to play. Forgive me if I get these dates wrong as my knowledge of computers is abysmal, but my memory says that we were advised that the bridge has never failed to open when required until the process was computerised. When the operation was changed from Windows 95 to 97 the bridge opened and then stuck there. It remained stuck for eleven hours while the software was sorted out.
Next we were down to the engine room. The story here is remarkable. The main bridge bearings have never been changed. They are (probably) the first caged bearings in the world. The lifting equipment is that which was installed when the bridge was completed in 1894. This old engine is one of six no longer in use as the drive has been replaced with electric engines and oil hydraulics rather than the original coal fired steam engines and water hydraulics for reasons of avoiding pollution and much needed improved efficiency. However, the drive is connected directly to the drive shaft of 1894. The coupling between the old engine and the drive shaft was cut with a gas axe.
This is one of the accumulators which was charged by the steam engines (with our guide). There were eight accumulators, and when fully charged they could operate the bridge lifts for about three weeks without the use of the steam engines in the event of "industrial action", which was not all that unusual, apparently.
Then to the vast bascule chamber. The sound of the river traffic was very noticeable - through 18 ft of masonry! No one knows for certain what the grooves are for. They don't appear on any drawings. The belief is that they may have been introduced when the bascules were being built. The bascules were built vertically so that the river traffic was not compromised and it is suspected that they were let down initially with chocks and wedges - the bottom of the groove appears smooth whereas the top is irregular. In preparation for the public opening of the bascule chamber a light was fitted on each wall outside the tunnels. Clearances are so tight that the inspection after a lift once the lights had been installed showed them all to have been smashed. That's probably around 6 inches each side.
Finally, back to the public area and the beautifully restored steam engines. Two remain but one has been removed and is now in a museum.
A piece of engineering which at 120 years old is still doing the job for which it was designed. I can't recommend this too highly. If you get the opportunity you've gotta do it.
Brian
I'm publishing this on WT because, although peripheral, it does involve some amazing engineering.
Here's a selection of the one hundred plus photos I took.
First of all one has to do the tourist bit. That includes walking across both the high level walkways with views up and down the river but also through the new glass floor.
Then in to one of the towers where the architecture has been exposed and some effort made to show the internal complexities of the building.
Then the engineering tour proper for which the guide was a real bridge engineer - not the greatest presenter but a man who knows the bridge inside out. This is the old control room, no longer in use but retained. It's similarity to a signal box is very marked. These levers operated not only the lifting of the bascules but the withdrawing of the bolts which hold the bridge at the joint. There is a cam which lifts the bridge off the bearings for road traffic and the lift itself requires several lever movements as different levels of stored power are brought in to play. Forgive me if I get these dates wrong as my knowledge of computers is abysmal, but my memory says that we were advised that the bridge has never failed to open when required until the process was computerised. When the operation was changed from Windows 95 to 97 the bridge opened and then stuck there. It remained stuck for eleven hours while the software was sorted out.
Next we were down to the engine room. The story here is remarkable. The main bridge bearings have never been changed. They are (probably) the first caged bearings in the world. The lifting equipment is that which was installed when the bridge was completed in 1894. This old engine is one of six no longer in use as the drive has been replaced with electric engines and oil hydraulics rather than the original coal fired steam engines and water hydraulics for reasons of avoiding pollution and much needed improved efficiency. However, the drive is connected directly to the drive shaft of 1894. The coupling between the old engine and the drive shaft was cut with a gas axe.
This is one of the accumulators which was charged by the steam engines (with our guide). There were eight accumulators, and when fully charged they could operate the bridge lifts for about three weeks without the use of the steam engines in the event of "industrial action", which was not all that unusual, apparently.
Then to the vast bascule chamber. The sound of the river traffic was very noticeable - through 18 ft of masonry! No one knows for certain what the grooves are for. They don't appear on any drawings. The belief is that they may have been introduced when the bascules were being built. The bascules were built vertically so that the river traffic was not compromised and it is suspected that they were let down initially with chocks and wedges - the bottom of the groove appears smooth whereas the top is irregular. In preparation for the public opening of the bascule chamber a light was fitted on each wall outside the tunnels. Clearances are so tight that the inspection after a lift once the lights had been installed showed them all to have been smashed. That's probably around 6 inches each side.
Finally, back to the public area and the beautifully restored steam engines. Two remain but one has been removed and is now in a museum.
A piece of engineering which at 120 years old is still doing the job for which it was designed. I can't recommend this too highly. If you get the opportunity you've gotta do it.
Brian
Classic!! 
(& that was many years ago, as there's a 7.5t weight limit on it, I think.)
